المواضيع

Amphibians 

It is a group of animals that belong to the vertebrate family , where these animals are distinguished by their ability to live in water and on land, and the name amphibians comes from the Greek word that means living a double life, as about 8100 species of living amphibians are known, and these animals appeared before about 340 million years ago during the Mississippi era, and among these animals are frogs, salamanders, cecilia and other species, and these animals have many characteristics, including wet skin, where amphibians depend on skin breathing and have green eyes in order to distinguish shapes, and some types of these animals live in stagnant water and put Their eggs are in the water, while others lay eggs under the skin of the female, and more about these animals will be explained in this article. 

Information about amphibians

amphibian characteristics

 Amphibians are animals that live in both water and land, where these animals lay eggs in the water or are carried by the female, and the eggs are surrounded by several membranes, and in the absence of these membranes, the process of reproduction of amphibians requires bodies of water, and these animals tend to live in wet places and that Because of maintaining the moisture of its skin, the smallest amphibian animal in the world was discovered, the frog , which was first discovered in Guinea in 2012, with an average length of 7.7 mm. The Chinese salamander is also one of the largest of these animals, with a length of 1.8 meters. These animals are cold-blooded, in addition to a low metabolic rate and as a result their food and energy requirements are limited, and adult species of these animals have tear ducts and mobile eyelids, and most types of amphibians have ears so that vibrations can be heard around them, and they have tongues Muscular, which can be protruded in many species, and its ribs are usually short and can be fused into the vertebrae, its skulls are mostly broad and short, and the skin contains many mucous glands and in some species they are poisonous glands. Amphibians have three-chambered hearts; Two atria and one ventricle, it also has a urinary bladder so that it excretes nitrogenous waste, and these animals breathe through the gills, and gas can be exchanged through the skin.

Metamorphosis in amphibians 

Most amphibians go through the process of metamorphosis, which is a major morphological change process that occurs after birth, where the eggs are laid in the water, and then the larvae adapt to the aquatic lifestyle, where frogs and salamanders hatch from the eggs as larvae. Through the concentration of thyroid hormone in the blood, which stimulates the process of metamorphosis, as most of the embryonic development is outside the body of the female and this development undergoes many modifications due to the conditions surrounding the larva, for this reason tadpoles can have horns instead of teeth or can have Fins, after the transformation process, these organs become redundant for the body's needs, so they are eliminated.

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